首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   8507篇
  免费   552篇
  国内免费   576篇
化学   152篇
晶体学   4篇
力学   425篇
综合类   121篇
数学   7888篇
物理学   1045篇
  2025年   24篇
  2024年   46篇
  2023年   111篇
  2022年   112篇
  2021年   113篇
  2020年   204篇
  2019年   223篇
  2018年   186篇
  2017年   226篇
  2016年   209篇
  2015年   191篇
  2014年   375篇
  2013年   650篇
  2012年   394篇
  2011年   420篇
  2010年   386篇
  2009年   486篇
  2008年   587篇
  2007年   583篇
  2006年   493篇
  2005年   494篇
  2004年   371篇
  2003年   386篇
  2002年   306篇
  2001年   271篇
  2000年   238篇
  1999年   227篇
  1998年   222篇
  1997年   210篇
  1996年   138篇
  1995年   89篇
  1994年   75篇
  1993年   61篇
  1992年   55篇
  1991年   57篇
  1990年   32篇
  1989年   31篇
  1988年   34篇
  1987年   20篇
  1986年   26篇
  1985年   41篇
  1984年   30篇
  1983年   22篇
  1982年   27篇
  1981年   31篇
  1980年   19篇
  1979年   26篇
  1978年   24篇
  1977年   17篇
  1976年   16篇
排序方式: 共有9635条查询结果,搜索用时 0 毫秒
61.
62.
Let B be the open unit ball of a complex Banach space X and let B be homogeneous. We prove distortion results for normalized convex mappings f:BX which generalize various finite dimensional distortion theorems and improve some infinite dimensional ones. In particular, our results are valid for the open unit balls of complex Hilbert spaces and the Cartan domains.  相似文献   
63.
指派矩阵同解改造理论变换定理论证   总被引:1,自引:0,他引:1  
本文对指派问题的“周良泽算法”赖以成立而又尚未具体证明的一个重要的基础性定理,给出了严谨的论证,对指派矩阵同解改造理论作了抬遗补证的工作。  相似文献   
64.
The fluctuation-dissipation theorem is not expected to hold for systems that either violate detailed balance or have time-dependent or nonpotential forces. Therefore the relation between response and correlation functions should have contributions due to the nonequilibrium nature. An explicit formula for such a contribution is calculated, which in the present derivation appears as a historydependent term. These relations are the Ward-Takahashi identities of a supersymmetric formulation of the Langevin models, and the new term results from a broken supersymmetry.  相似文献   
65.
In this paper, we study the thermal properties of the inner horizon of a Kerr-Newman black hole. By adopting Damour-Ruffini method and the thin film model which is developed on the base of brick wall model suggested by ’t Hooft, we calculate the temperature and the entropy of the inner horizon of a Kerr-Newman black hole. We conclude that the temperature of inner horizon is positive and the entropy of the inner horizon is proportional to the area of the inner horizon. The cut-off factor is same as it in calculation of the entropy of the outer horizon, 90β. In addition, we write the integral and differential Bekenstein-Smarr formula as the parameters of the inner horizon. Then, we discuss that if the contribution of the inner horizon is taken into account to the total entropy of the black hole, the Nernst theorem can be satisfied. At last, We calculate the tunneling rate of the outer horizon Γ+ and the inner horizon Γ. The total tunneling rate Γ should be the product of the rates of the outer and inner horizon, Γ=Γ+⋅Γ. We find that the total tunneling rate is in agreement with the Parikh’s standard result, Γ→exp (ΔS BH ), and there is no information loss.  相似文献   
66.
Biot's consolidation theory is extended to a general class of viscoelastic bodies defined by Riemann-Stieltjes integral convolutions. From a new reciprocity theorem, proved for the governing equations including the inertia terms, the basic integral representations of the displacement fields and pore pressure are obtained. It is shown that, in the absence of internal inputs, a formulation of the dynamic problem in terms of the boundary unknown fields only is possible.  相似文献   
67.
In this paper, we give a direct proof of Rockafellar's result that the subdifferential of a proper convex lower-semicontinuous function on a Banach space is maximal monotone. Our proof is simpler than those that have appeared to date. In fact, we show that Rockafellar's result can be embedded in a more general situation in which we can quantify the degree of failure of monotonicity in terms of a quotient like the one that appears in the definition of Fréchet differentiability. Our analysis depends on the concepts of the least slope of a convex function, which is related to the steepest descent of optimization theory.The author would like to express his thanks to R. R. Phelps for reading a preliminary version of this paper and making some very valuable suggestions.  相似文献   
68.
An existence and uniqueness of solutions for boundary value problemsandare established, by employing a priori estimates for all solutions and the Schau-der fixed point theorem. Some of these results extend earlier results due toUsmani(1979), Yang(1988), and Pei(1997).  相似文献   
69.
For symmetric spaces of noncompact type we prove an analogue of Hardy’s theorem which characterizes the heat kernel in terms of its order of magnitude and that of its Fourier transform.  相似文献   
70.
In this paper we present a two-norms version of Krasnoselskii's fixed point theorem in cones. The abstract result is then applied to prove the existence of positive Lp solutions of Hammerstein integral equations with better integrability properties on the kernels.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号